Efficient Power Transmission with Existing Grid … Power Transmission with Existing Grid System of Bangladesh . ... power plant. Ruppur Nuclear Power ... develop and expand the same

Efficient Power Transmission with Existing Grid

System of Bangladesh

Aktabujjaman, S. Islam, and M. A. Ullah Electrical and Electronic Engineering, Chittagong University of Engineering and Technology, Chittagong, Bangladesh

Email: [email protected], {shakilcuet, ahsan_cuet}@yahoo.com

Abstract—Sustaining power quality with increasing demand

is becoming a challenge to power engineers. Effective

transmission and distribution of electrical power is the

major concern all over the world. Existing grid system of

Bangladesh utilizes about 49% of its capacity. It cannot run

with its full capacity due to poor voltage regulation. IEC

standard of voltage regulation is ±5% whereas power Grid

Company of Bangladesh (PGCB) allows ±10% voltage

regulation. It is shown that voltage regulation in some buses

lower than the PGCB standard even though PGCB uses

reactive power compensator to improve voltage regulation

problems of the grid system. This paper demonstrates how

voltage regulation improves by selecting suitable location of

power compensator in the existing grid. Relation between

voltage regulation and power consumption is also shown. If

three power compensators relocate in the grid system, the

voltage regulation increased on 32.62% of total load and no

busses experiences voltage regulation lower than PGCB

standard. Moreover, if the PGCB allows 464 MVAR more

reactive power compensator, the voltage regulation of the

power grid can achieve IEC standard (for the load

connected in the year of 2012) and if PGCB redesign

reactive power compensator it may reach IEC standard by

731 MVAR. The result shows in this paper is performed by

ETAP software. Index Terms—reactive power compensation, effective power

transmission, voltage regulation, power grid of Bangladesh,

I. INTRODUCTION

Bangladesh is presently facing shortage of power and

there are always load shedding in some parts of the

country. This is threatening to the agriculture, industry,

commerce as well as the whole economy. Average 16

terawatts (TW) electric power is being used every

moment throughout the world [1]. Generation of

electricity is costly. Efficient use of electricity must be

ensured. Now in Bangladesh maximum demand is about

7500 Megawatts (MW) or 7.5 Giga-watts (GW) [2]

corresponding generated power is not enough to meet the

present demand due to inadequate generation [2]. In the

year of 1995, 2001, 2006, and 2012, installed power

capacity was 2908MW, 4005MW, 5275MW, and

6693MW, respectively [3] and corresponding demand

served (rated capacity) is lower than installed capacity. In

Manuscript received March 7, 2014; revised September 24, 2014.

Bangladesh increase of energy demand in recent years is

noticeable than before shown in Fig. 1. Rising of energy

demand is a tension to policy makers. To fulfill the

commitment as declared in the Election Manifesto and to

implement the Power Sector Master Plan 2010,

Government has already been taken massive generation,

transmission and distribution plan [3]. The generation

target within 2016 is 13,154MW. When the present

government takes charge, the power generation was 3,200

to 3,400MW against national demand of 5,200MW [3].

This government is able to add 2,944MW of power to the

national grid within three years time period. According to

goal of 2021, the forecasted demand would be

19,000MW and 34,000MW in 2030. To meet this

demand the generation capacity should be 39,000MW in

2030.

Figure 1. Forecasted energy demand of Bangladesh [2].

In recent the government has approved installation of

five more coal-fired power projects by local private

sector entrepreneurs having a combined capacity to

generate 2,087MW of electricity. The Rampal power is a

proposed 1320 megawatt coal-fired power station at

Rampal upazila of Bagerhat district in Khulna. The

proposed project will be the country’s largest coal based

power plant. Ruppur Nuclear Power Plant is a proposed

2,000 megawatt (MW) nuclear power plant of

Bangladesh. It will go into operation by 2020 and will be

the country’s largest and first nuclear power plant.

500MW power is importing from India‘s grid to

Bangladesh‘s grid. PGCB is the coordinator of the import

International Journal of Electronics and Electrical Engineering Vol. 3, No. 5, October 2015

©2015 Engineering and Technology Publishing 336doi: 10.12720/ijeee.3.5.336-343

PGCB, national grid

process, said by the end of October-2013 around 250MW

of power would be imported into Bangladesh. Another

250MW was expected to be imported from India‘s

private sector by November this year [4].

The office of the Electrical Advisor and Chief

Electrical Inspector (EA & CEI) emphasizes on thrift,

simplicity and safety. It has been established, in order to

ensure proper control of life and property in generation,

transmission and distribution of electricity. The objective

of Energy Monitoring Unit is to ensure efficient use of

energy in industries and to induce energy conservation.

Bangladesh Power Development Board (BPDB),

Ashuganj Power Station Co., Ltd. (APSCL), Electricity

Generation Company of Bangladesh Ltd. (EGCB), Rural

Power Company Ltd. (RPCL), North West Power

Generation Company Ltd. (NWPGCL), Independent

Power Producers (IPPs) are work for generation. The

responsibility is to operate the national power grid and to

develop and expand the same with efficiency by Power

Grid Company of Bangladesh (PGCB). The PGCB also

handles the operation, maintenance and development of

the transmission system of the country for distribution of

generated electricity. The following entities are involved

in power distribution: Bangladesh Power Development

Board. (BPDB), Rural Electricity Board (REB), Dhaka

Electric Supply Co., Ltd. (DESCO), Dhaka Power

Distribution Co., Ltd. (DPDC), West Zone Power

Distribution Co., Ltd. (WZPDCL), North West Zone

Power Distribution Co., Ltd. (NWZPDCL), South Zone

Power Distribution Company Ltd. (SZPDCL). REB is

responsible for electrification in rural areas. As of today,

there are 70 operating rural electricity co-operatives

called Palli Bidyuit Samity (PBS), which bring service to

approximately 79,00,000 connections. REB has expanded

its distribution networks significantly in past years and

has thus made immense contribution in increasing

agricultural products and rural development as well as

economic contribution. PGCB take new steps of 400kV

line Meghnaghat-Aminbazar 400kV transmission line

(NG1) to evacuate power from Meghaghat power station

to western part of Dhaka. Bibiyana-Kaliakoir 400KV and

Fenchuganj-Bibiyana 230KV transmission line (NG2) to

build the power evaluation facilities for upcoming 2x450

MW at Bibiyana & to evacuate the surplus power of

Sylhet area and also to supply adequate power to the

northern part of Dhaka city [3].

The generated power is transmitted and distributed

from generating station to consumer end through

transmission and distribution line. During transmission

and distribution a large amount of power is loss (15.38%)

[3]. Due to the losses in lines causes the transmission

efficiency lower, poor voltage regulation i.e. power

quality is reduced. Reactive power compensation is one

of the techniques for improving power quality. Existing

grid is used 49% of its capability. Change in power grid

is costly and matter of time. The capability, problems,

possible solutions for optimum utilization of generated

power with existing grid system is described on this paper.

Eight reactive power compensators are installed

already in power grid of Bangladesh. But those are not

sufficient enough. Existing grid can make more stable by

relocating existing reactive power compensator.

Relocating three reactive power compensators, existing

grid can provide better voltage regulation across about

32.62% of total load. By placing new 464 MVAR

distributed reactive power compensator existing grid can

be improved to IEC standard. If we redistribute and add

new reactive power compensator, minimum 731 MVAR

might require to reach IEC standard voltage regulation.

In this paper Section II, III, IV described power system

of Bangladesh (capability, problem). Section V described

Rearrangement of Existing Grid of Bangladesh, making

existing grid to IEC standard is shown in Section VI,

Newly arranged reactive power compensator to make

existing grid to IEC standard is shown in Section VII,

results and conclusion is shown in next section.

Simulation is performed by ETAP software.

II. TRANSMISSION LINE IN BANGLADESH

The purpose of transmission line is to transfer electric

energy from generating station to distribution substation.

Most of the transmission lines of Bangladesh are short

and medium transmission line [5]. Standard transmission

voltages are established in the United States by the

American National Standards Institute (ANSI) which is

standardized at 69KV, 115kV, 138kV, 161KV, 230KV,

345KV, 500KV, and 765KV. Transmission voltage

usually above 230KV is usually referred to as Extra High

voltage. The existing transmission voltage levels in

Bangladesh are 66KV, 132KV, 230KV, and 400kV

(under construction) [6]. Transmission line of 132 kV is

6066.44 Circuit km and of 230kV is 2647.3 Circuit km

[7]. When the length of overhead transmission line is up

to about 50km and the voltage level is comparatively low

(<20kV) is known as short transmission line. When the

length of overhead transmission line is up to about 50-

150km and the voltage level is moderately high

(<20kV<100kV) is known as medium transmission line.

When the length of overhead transmission line is up to

more than 150km and the voltage level is high (<100kV)

is known as long transmission line [8].

According to the definition in Bangladesh all of the

transmission line voltage level is long transmission line

category and in length is medium and long transmission

line category. Existing power grid is shown below in Fig.

2.

III. VOLTAGE REGULATION

Voltage regulation is an important subject in electrical

distribution engineering. It is the responsibility to keep

the customer voltage within specified tolerances. The

performance of a power system and quality of the service

provided are not only measured in terms of frequency of

interruption but in the maintenance of satisfactory voltage

levels at the customers.


©2015 Engineering and Technology Publishing 337

Figure 2. Power grid network of Bangladesh.



Figure 3. Behavior of resistive load and inductive load with voltage regulation.

According to Gonen [9] an over voltage can reduce

lighting bulb life and reduce the life of electronic devices.

On the other hand, a low voltage leads to low

illumination levels, shirking of television pictures, slow

heating of heating devices, motor starting problems, and

overheating in induction motors. However, most

equipment and appliances operate satisfactorily over

some reasonable range of voltages. In resistive load

power consumption become lower as shown in Fig. 3.

When system voltage is less than rated voltage and higher

for above the rated voltage, induction motors and

synchronous motors power consumption is independent

of voltage i.e. consume same power whether voltage is

lower or higher than rated voltage. Over voltage can

cause insulation failure of motor winding, low voltage

can permanently damage the motor winding. Fig. 3 is

obtained from simulation for resistive load and inductive

load at different voltage from 110% to 80% of their rated

voltage i.e. -9.09% to +25% of voltage regulation. IEC

standard voltage regulation is ±5% and where in

Bangladesh PGCB standard is ±10%. From the Fig. 3, it

is clear that if generation is sufficient but due to poor

voltage regulation in bus, equipment cannot run at full

power rating although generating unit has capability.

A. Real Power

Real power is output power of a utility or electrical

equipment i.e. heat, light, radiation, vibration, rotation etc.

B. Reactive Power

Reactive power is required to work real power

effectively. Reactive power represents the energy that is

first stored and then released in the magnetic field of an

inductor, or electrical field in capacitor. Reactive power

is used to provide the voltage levels necessary for active

power to do useful work [10].

C. Limitations of Reactive Power

Although reactive power has great importance on

voltage control of power system but it cannot travel far.

Flowing of reactive power causes loss of real power. The

capability of transmission line is limited by the current

carrying capacity of the conductor. If more reactive

power supplied through the transmission line it will limit

the real power flow and causes more real power loss [11].

D. Transmission Efficiency

The power obtained at the receiving end of a

transmission line is less than the sending end power due

to losses in the line. The ratio of receiving end power to

the sending end power of a transmission line is known as

the transmission efficiency of the line [8], [12].

Percentage (%) efficiency



=Receiving end power

Sending end power×100

=cos

cos

R R R

S S S

V I

V I

×100

where, R R RV ,I ,cos are the phase voltage, current and

power factor at receiving end of transmission line

respectively. S S SV ,I ,cos are the sending end phase

voltage, current and power factor, respectively. Receiving

end real power [11] is given by

2

cos cosS R RR

V V AVP = β -δ - β -α

B B

The receiving end reactive power is represented by

2

sin sinS R RR

V V AVQ = β -δ - β -α

B B

Receiving end reactive power is square proportional of

receiving voltage. Here real power and reactive power

(PR, QR) both are function of VR. Similarly same result

can obtain for medium and long transmission line.

IV. POWER GRID SYSTEM OF BANGLADESH

A. Capability of Existing Power Grid System

The maximum power can be transmitted or received

through a line is known as power handling capability.

Power handling capability of transmission line,

= 3 L LV I VA

where, VL, IL are rated voltage and maximum current

capacity, respectively, of conductor.

Power handling capacity depends upon some factors

such as length of cable, thermal withstand capability,

weather condition. One cable can transfer different power

at different voltage level. In this paper total

interconnected grid system capability equal to

transformer MVA rating of entire grid system which is

15821MVA [7]. It is a fact that, the national grid of

Bangladesh is transferred maximum of 7852MVA, which

is 49% of the existing capacity of the connected

equipment of the system (6675.00MW at 0.85 p.f) [2]. On

the other hand, the reserve capacity of the equipments is

7968MVA, whereas 51% of the existing capacity of the

grid (shown in Fig. 4).

Figure 4. Equipment used in the system and reserve capacity.

B. Existing Grid System Problem

Low power factor

Most of the reactive power generated at power

plant

Most of the Generators are concentrated in a place.

Existing Capacitive bank (reactive compensator) is

not enough to compensate the reactive power.

Generating stations are far from load centre. Line

current is high for carrying reactive power.

Generation of real power is reduced due to

generation of excess reactive power.

From the above study it is clear that although PGCB

grid has capability of handling much power but it cannot

transmit power effectively.



E. Short Transmission Lines [8]

A = 1, B = Z, β ≈ 90°, α ≈ 0°.

Hence, cos β α 0

2

cos cosS R RR

V V AVP = β -δ - β -α

B B

cosS RV Vβ - δ

B

cos 90S RV Vδ

B

sinS RV Vδ

B

For constant load VS, δ and B are constant.

Hence,

R RP V

Receiving end real power is proportionally related with

receiving end voltage.

Receiving end reactive power [13]

sin sin2

S R R

R max

V V AVQ β -δ β -α

B B

At maximum load, β = δ

2

sinR

R max

AVQ β -α

B

Hence,

2

RR maxQ V

Figure 5. Comparison of modified system and existing system

V. REARRANGEMENT OF REACTIVE POWER

COMPENSATOR OF EXISTING GRID

Eight substations contain capacitor bank in national

grid of Bangladesh. Total capacity is 450 MVAR. Ishordi,

Khulna South, Jessore, Barisal, Madaripur and Hathazari

have single 45 MVAR capacitor bank and Aminbazar and

Rampura have two 45 MVAR capacitor bank. Simulation

result shows that Panchagorh, Thakurgoan, Niamotpur,

Joypurhat and Cox-bazar grids’ voltage level is below

PGCB standard. In this paper three capacitor banks is

rearranged or relocated from Khulna to Saidpur,



Madaripur to Bhandaria and Hathazari to Khulsi.

Performance comparison between rearranged and existing

grid is shown in Fig. 5. The graph is plotted for all buses

in Bangladesh.

A. Region 1

In region 1, modified system shows better performance

over existing system. About 11.93 % of total load is

connected in this region. In existing grid system some of

the buses are below of PGCB voltage regulation standard

but in modified grid system all the buses within PGCB

standard limit. The voltage regulation in region 1 is better

than existing system. Region 1 contains Panchaghar,

Thakurgaon, Purbasadipur, Bogra, Bogra new, Saidpur,

Rangpur, Barapukuria, Lalmonirhat, Natore, Palashbari,

Noagoan, Niamotpur, Joypurhat, Rajshahi, Chapai

Nawabgonj, Sirajgong Switching, Sirajgong, Shahjadpur

grid [14].

B. Region 2

In region 2, modified system performance slightly

degrades. About 4.42% of total load is connected in this

region. Despite of this degradation, it has no significant

effect on grid. Because in this region, the voltage

regulation is within IEC standard limit as well as PGCB

standard limit. All bus voltage magnitude is above 95%.

Region 2 contains Noapara, Khulna South, Khulna

Central, Satkhira, Gallammari and Goalpara grid.

C. Region 3

In region 3, modified system performance is degraded.

About 5.55% of total is connected in this region. In

existing system, all the bus voltage regulation within

PGCB standard. In modified system all bus voltage

regulation is also within the PGCB standard. It has slight

effect on grid. Region 3 conatains Patuakhali, Barishal,

Madaripur, Gopalgong, Faridpur, Baghabari,

Mymensingh RPCL, Mymensingh and Bagherhat grid.

D. Region 4

In region 4, modified system performance is

considerably better than the existing grid system. About

20.69% of total load is connected in this region. In this

region all bus voltage is increased. Region 4 contains

comilla north, Comilla south, Chandpur, Feni,

Chowmohuni, Hathazari, KSRM, Baraulia, Madunaghat,

Abul Khayer, Khulsi, Halishohor, Shikalbaha, Julda,

Shahmirpur, Dohazari and Coxbazar grid.

E. Result

Although modified grid system have slightly less

performance in region 2 and region 3, but significant

effect on region 1. In modified grid system all the buses

in region 1 is within the PGCB limit which was not in

existing grid system. The load contribution of region 1 is

more than the sum of region 2 and 3. In region 4, system

is more reliable and stable. So, it is clear that the

modified grid system has better performance than

existing grid system.

VI. PROPOSAL FOR MAKING EXISTING GRID TO IEC

STANDARD

In this paper simulation is performed for 4523MW

(consider base load). Peaking power plant in Saidpur,

Rangpur is in service. To improve the power grid voltage

regulation into IEC standard, reactive power compensator

is distributed throughout the grid. A table of distributed

reactive power compensator is given below which is

performed in simulation. In this paper MVAR per

capacitive bank is 7MVAR and 10MVAR for switching

convenient. Minimum 464MVAR is required existing

grid improved to IEC standard. The grid response is

shown in Fig. 6. Approximate reactive compensator

required is shown in Table I.

Figure 6. Comparison of IEC standard of existing grid.

TABLE I. EXISTING GRID TO IEC STANDARD

Grid Name Required MVAR

Grid Name Required MVAR

Joypurhat 14 Niamotpur 14

Noagoan 40 Manikgong 20

Mongla 10 Joydevpur 30

Patuakhali 7 Ullon 20

Bhandaria 7 Dhanmondi 30

Kabirpur 30 Khulsi 30

Tangail 28 Halishahar 28

Bagherhat 10 Dohazari 7

Chuadanga 7 Coxbazar 14

Ch. Nawabgong 20 Comilla South 40

Rajshahi 10 Chandpur 28

Total 464 MVAR

A. Result

Existing power grid have total 450 MVAR reactive

power compensator and additional 464MVAR i.e. 914

MVAR can be made grid to IEC standard.

VII. NEWLY DESIGN REACTIVE COMPENSATOR FOR

MAKING EXISTING GRID TO IEC STANDARD

In these section reactive compensators is distributed

among all bus including existing reactive compensators.

The grid response is shown in Fig. 7. Table shows

required minimum MVAR to achieve IEC standard.

Approximately minimum 731 MVAR may be required to

reach IEC standard is shown in Table II.

Figure 7. Newly design grid response

TABLE II. NEWLY DESIGN REACTIVE POWER COMPENSATOR

Grid Name Required

MVAR

Grid Name Required

MVAR

Noagoan 20 Manikgonj 14

Niamotpur 7 Savar 10

Natore 7 AminBazar 40

Rajshahi 14 Shampur 7

Ch. Nawabgonj 7 Dhanmondi 40

Jhinaidoh 21 Moghbazar 20

Chuadanga 7 Rampura 40

Magura 7 Comilla South 50

Jessore 20 Chandpur 28

Mongla 7 Feni 10

Bhandaria 10 Chowmohuni 10

Patuakhali 10 Hathazari 20

Barishal 28 Baraulia 10

Madaripur 30 Khulsi 50

Gopalgong 7 Halishohor 20

Faridpur 14 Julda 30

Joydevpur 21 Dohazari 7

Kabirpur 50 Coxbazar 10

Tangail 28 Manikgonj 14

Savar 10

Total 731 MVAR

A. Result

In new design 731 MVAR is required. It saves 183

MVAR less compared to earlier design.

VIII. CONCLUSION

Energy demand and supply is increasing, reliability

and efficiency are ongoing problems. 49% of existing

grid is used up to now. Reactive power compensator can

improve voltage regulation problem and make system

stable. Relocation of three capacitor bank can improve

voltage regulation across 32.62% of total load and

degrade voltage regulation across 9.97% of total load.

Where 4.42% load is within the IEC standard. Placing

distributed reactive power compensator (minimum

464MVAR total 914 MVAR) can improve existing grid

to IEC standard. Minimum 731 MVAR is required to

reach IEC standard for newly design compensation

system.

Simulation results demonstrate the effectiveness of the

proposed system. Proposed modification and placing

proper size of reactive power compensator make system

stable and can provide increasing power demand by

existing power grid without compromising the power

quality.

ACKNOWLEDGMENT

First of all we greatly thankful to almighty ALLAH,

for kindness, giving patience, ability, knowledge and

keep us healthy. We would like to like to thank Engineer

Md. Manzur Morshed, Deputy Manager (Technical) of

odunaghat substation of PGCB (Ctg), Mr. Kanai Kanti

Das, Mr. Mithu assistant Engineer at Raozan Thermal

Power Plant for proving valuable information and time,

Nuruddin Md. Forhad Chowdhury (DM) Hathazari

substation, Md. Shahin DM (Protection) Agrabad, PGCB

(Chittagong) for providing transmission line parameter

and data, Mohammad Hossain (JAM), Md. Faisal Abedin

(JAM), Md. Solaiman Hossain (PGCB Saidpur) for

helping us from their valuable time.

REFERENCES

[1] Electricity sector in Bangladesh. [Online]. Available:

http://en.wikipedia.org/wiki/Electricity_sector_in_Bangladesh

[2] Bangladesh Power Development Board. [Online]. Available:

http://www.bpdb.gov.bd [3] Power Cell. [Online]. Available: http://www.powercell.gov.bd

[4] DhakaTribune. [Online]. Available: http://www.dhakatribune.com

[5] A. Hussain, Electrical Power Systems, 5th ed, CBS Publishers & Distributors Pvt. Ltd., 2010.

[6] H. Sadat, Power System Analysis, WCB/McGraw-Hill, 1999. [7] Power Grid Company of Bangladesh Limited. [Online]. Available:

www.pgcb.org.bd

[8] V. K. Mehta and R. Mehta, Principles of Power System, S. Chand, 1982.

[9] T. Gonen, Electric Power Distribution System Engineering, New

York: McGraw Hill, 1986. [10] Electrical notes and articles. [Online]. Available:

https://electricalnotes.wordpress.com/2011/03/21/importance-of-

reactive-power-for-system/ [11] S. J. Chapman, Electric Machinery Fundamentals, 4th ed.,

McGraw-Hill, 2005.

[12] G. T. Heydt, Electric Power Quality, 2nd ed., West LaFayette, IN: Stars in a Circle Publications, 1991.

[13] William D. Stevenson, Elements of Power System Analysis, Jr.

Fourth Edition, McGraw Hill, 1982. [14] GET INTO PC. [Online]. Available:

http://getintopc.com/softwares/electrical-engineering/etap-free-

download/

Aktabujjaman received B.Sc. in Electrical and Electronic Engineering from Chittagong

University of Engineering and Technology,

Bangladesh in 2012. He worked as Lecturer at IBAIS University,

System Engineer at GrameenPhone Limited

and Trainee Engineer at Horipur Combine Cycle Power Plant (360 MW). Currently he is

working as Assistant Engineer, system

protection and metering division at Power Grid Company of Bangladesh Limited (PGCB). His interest to be an expert

in power system.





Md. Saidul Islam is born in Bogra, Bangladesh. He received B.Sc. in Electrical and Electronic

Engineering from Chittagong University of

Engineering and Technology, Bangladesh in 2012. Currently he is working as Shift Engineer

in Samuda Chemicals Complex Limited,

Meghnaghat, Munshigong. He wanted to technically sound engineer.

Muhammad Ahsan Ullah received B.Sc. inEngineering degree in Electrical and Electronic

Engineering from Chittagong University of

Engineering and Technology, Bangladesh in2002, M.E. degree in Electronic and

Information Engineering from Kyung Hee

University, Republic of Korea in 2007 and PhDdegree in Electrical Engineering at Nagaoka

University of Technology at 2011. He is

interested in Signal Processing, Coding Theory, Threshold Decoding,MCCDMA, OFDMA, MIMO, and Image Processing.

Documents

Efficient Power Transmission with Existing Grid … Power Transmission with Existing Grid System of Bangladesh . ... power plant. Ruppur Nuclear Power ... develop and expand the same